Ajax模式弹出扩展器在IE 8中不工作

我该怎么办?

环境:Windows7X32,VS2008SP1,.NETFramework 3.5SP1。

谢谢

编辑 在updatepanel的contenttemplate中,我有一个listview,其itemtemplate是:

<ItemTemplate>
                    <td>
                        <asp:Image Width="200px" Height="200px" ID="thumbnail" runat="server" ImageUrl='<%# "../LoadImage.ashx?t=myImage&ids=" + Eval("Id") %>' />
                        <cc1:ModalPopupExtender ID="Image1_ModalPopupExtender" runat="server" DynamicServicePath=""
                            Enabled="True" PopupControlID="panel_bigImage" TargetControlID="thumbnail"
                            DropShadow="False" OkControlID="BigImage" CancelControlID="btnCloseImage" >
                        </cc1:ModalPopupExtender>
                        <asp:Panel ID="panel_bigImage" runat="server" DefaultButton="btnCloseImage" EnableViewState="True" HorizontalAlign="Center" ScrollBars="Auto" BorderStyle="Outset" BackColor="White">
                            <asp:Image ID="BigImage" Height="600px" runat="server" ImageUrl='<%# "../LoadImage.ashx?t=myImage&ids=" + Eval("Id")%>' />
                            <br />
                            <asp:Button ID="btnCloseImage" runat="server" Text="Inchide" />
                        </asp:Panel>
                    </td>
</ItemTemplate>